Improvement in processes of hardening edge tools



1 UNITED STATES PATENT OFFICE.

LEVERETT W. STUART, or HAWLEY, PENNSYLVANIA, ASSIGNOR T0 GUSTAVUS AMES, OF ROCHESTER, NEW YORK.

IMPROVEMENT IN PROCESSES OF HARDENING EDGE TOOLS.

Specification forming part of Letters Patent No. 140,390, dated July 1, 1873; application filed June 27, 1872.

To all whom it may concern Be it known that I, LEVERETT W. STUART,

' of Hawley, in the county of Wayne and State of Pennsylvania, have invented a new Process of Hardening Edge Tools, of which the following is a specification The invention will first be fully described in connection with all that is necessary to a full understanding thereof, and then clearly pointed out in the claim.

After much thought and careful experiment, for the purpose of attaining some convenient Way of densifying and hardening the cuttingedge of edge tools, harvester-cutters, and sawteeth, I have discovered a process by which it may be done eflectuall y and with little labor and cost.

This process consists in holding the previously hardened and tempered blade with the part that is to be hardened against a revolving smooth-faced metallic wheel. The wheel revolving against the metal edge indurates it to such an extent that it will resist effectually the ordinary action of a file.

If a tool like a harvester-blade is to be operated upon, it is hardened and tempered first in the ordinary manner. The horizontal face of the edge is then held to the revolving wheel until the desired degree of hardness is obtained. On the other hand, if a saw-tooth is to be treated, I take the steel-pointed tooth,

and place the outer face that takes the wear and subject it to the same induration.

Having thus described my invention, what I claim as new, and desire to secure by Let ters Patent, is-

The process of hardening edge tools, by ap- 

